Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

other elevated bodies, the evidence of its lowest positive pres- sure is to be sought still higher; i. e., more elevated from the ground. The air and the earth are believed to be, as a whole, charged with different electricities, which are continually tending to re- combine, and are perpetually doing so, by varied degrees, in the lower strata of the air, some directly by the dry land, but much more through good conducting bodies that are upon the surface of the earth. This is because our globe is magnetic, and charged with negative electricity (magnetic ?), although constantly unit- ing with the positive of the air; so that over all the surface of our earth, for a very few feet deep, the air is found at a near balance, i. e., neither positive nor negative, and the needle of the electrometer is here almost constantly at zero. Now, we see that if each drop of rain, or each flake of snow, is of the same kind of electricity with which the globules of the clouds were charged, and of which they had indeed served to form a part, — the whole even, by their agglomeration, — it is easy to conceive how there is an electric change brought about with every fall of rain, hail, or snow, since this is carried onward with them in their fall. Each drop of rain, and each flake of snow, is doing a work that not only causes the electrom- eter and the barometer to fluctuate, but also causes joints, nerves, and bones to feel and confess their united power. Says De la Rive, wherever it rains there is a region of country, or sea, that for the time is charged with positive electricity; that this region is completely surrounded by a zone on all its border, but entirely oxitside the rain and storm, that is, charged with the negative electricity. Suppose there is rain falling at a very great distance from the place of observation, but which is approaching, and then soon arrives there under the action of the wind, and then passes onward and over without ceasing to fall, until all is passed. In that case, the following is the order in which it occurs, i. e., as the storm clouds approach and pass away: — 1. When the rain is very distant, the instruments indicate positive electricity in the air, as they do almost always, and even this with some considerable degree of tension.